Question to the Cabinet Office:

To ask His Majesty's Government what percentage of Government Major Projects Portfolio projects have been re-baselined in the past year.

The Infrastructure and Projects Authority estimates that approximately 61% of Government Major Projects Portfolio (GMPP) have been re-baselined between 31 March 2023 and 31 March 2024. This rate of change is explained by 3 reasons:

1. Major projects report a cost baseline that factors in inflation expectations. Each year these expectations have to be revised as inflation forecasts are revised, which in turn leads to a cost baseline revision.

2. Major projects are the most challenging, ambitious and innovative projects the UK has ever seen, with the scale and scope matching some of the biggest in the world. This challenge is therefore associated with a significant level of uncertainty, which leads to frequent cost baseline revision.

3. A large number of projects are at the pre-delivery stage, where they are expected, and encouraged, to change their baseline when they are in order to ensure that their plans are correctly set out at the delivery stage.